728847661 has 2 divisors, whose sum is σ = 728847662. Its totient is φ = 728847660.

The previous prime is 728847599. The next prime is 728847697. The reversal of 728847661 is 166748827.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 640393636 + 88454025 = 25306^2 + 9405^2 .

It is a cyclic number.

It is not a de Polignac number, because 728847661 - 2¹³ = 728839469 is a prime.

It is equal to p_37667956 and since 728847661 and 37667956 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (728847061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364423830 + 364423831.

It is an arithmetic number, because the mean of its divisors is an integer number (364423831).

Almost surely, 2^728847661 is an apocalyptic number.

It is an amenable number.

728847661 is a deficient number, since it is larger than the sum of its proper divisors (1).

728847661 is an equidigital number, since it uses as much as digits as its factorization.

728847661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 903168, while the sum is 49.

The square root of 728847661 is about 26997.1787600112. The cubic root of 728847661 is about 899.9373046862.

The spelling of 728847661 in words is "seven hundred twenty-eight million, eight hundred forty-seven thousand, six hundred sixty-one".